Our objective is to uncover molecular mechanisms in lysosome biogenesis and fusion. Specifically, lysosomal and nonlysosomal glycosidases will be investigated in relation to the pathways of glycoprotein biosynthesis in mammalian tissues. The several alpha-D-mannosidases and alpha-D-glucosidases will be studied with oligosaccharide substrates, particularly the biosynthetic intermediates which need to be trimmed during their conversion to the mature products. In addition, the efficient in vitro Acanthamoeba phagolysosome fusion system will be further investigated. Since recent findings indicate involvement of cyclic nucleotides in determining the rate of fusion, the possible participation of a cAMP-dependent phosphorylation of the lysosomal membrane or cytosolic enzyme in enhancing fusion will be investigated.